This invention relates generally to a sloped wall or roof structure for supporting glazing panels of the type generally used in vertical curtain wall systems.
Prior art sloped glazing structures generally employ rafters which form a framework for the panels. However, prior art structures suffer from the disadvantage that these panels are generally made of glass so that they expand and contract at a different rate than the metal rafters, such rafters generally being fabricated from aluminum. This difference in the rates of expansion and contraction can contribute to the problems created by water collected along the rafters, and on the underside or inside of the glazing panel, in that the structure must be provided with means for carrying off this moisture to a gutter system associated with such a sloped glazing structure.
Prior art U.S. Pat. No. 4,070,806 illustrates a rather complicated solution to this problem wherein an internal gutter is provided within the cornice portion of the sloping roof structure, and wherein the rafters are equipped with integrally formed channels or gutters for carrying the water to the horizontally extending gutter at the roof cornice.
The present invention seeks to solve the problem to which the disclosure in prior art U.S. Pat. No. 4,070,806 is directed without such an internal gutter and without sacrifice to the complexity of the joints required between the rafters and the existing vertical curtain wall structure. Whereas many sloped glazing structures require mitering and welding of joints between the inclined rafters, and between the rafters and the purlins, as well as between the rafters and the vertical curtain wall itself, the relatively simple structure of the present invention avoids this necessity, and also avoids the complex internal gutter system of the above mentioned prior art patent.
Another advantage of the present invention is the unique horizontally extending top rail configuration which facilitates joining of the sloped glazing structure to an existing vertical wall. Not only does the present disclosure provide a conventional external gutter, which can receive moisture from the underside of the glass panels in the sloped glazing structure, but the configuration of the cornice structure itself, particularly the top rail portion of the sloped glazing structure, provides a very pleasing appearance. In addition to including this unique means for disposal of water collected by the uniquely configured rafters and purlins utilized in the present structure the present invention provides a more efficient and economic overall roof structure.